Bradabyssa alaskensis, Salazar-Vallejo, 2017

Salazar-Vallejo, Sergio I., 2017, Revision of Brada Stimpson, 1853, and Bradabyssa Hartman, 1967 (Annelida, Flabelligeridae), Zootaxa 4343 (1), pp. 1-98 : 29-30

publication ID

https://doi.org/ 10.11646/zootaxa.4343.1.1

publication LSID

lsid:zoobank.org:pub:6E46EE12-D51F-48B0-BC66-0EBBAF9FA981

DOI

https://doi.org/10.5281/zenodo.6051143

persistent identifier

https://treatment.plazi.org/id/038B87B6-347A-FFB1-1AB7-FC5FFB43F938

treatment provided by

Plazi

scientific name

Bradabyssa alaskensis
status

sp. nov.

Bradabyssa alaskensis View in CoL n. sp.

Figure 12 View FIGURE 12

Type material. Arctic Ocean, Northern Alaska . Holotype ( LACM 2598 ) and two paratypes ( LACM 2599 ), Aleutian Islands Cruise, Sta. 109 (71º34' N, 162º53' W), 140 km NNW off Icy Cape (250 km W off Point Barrow ), 42 m, silty clay sediment, 19 Aug. 1949. GoogleMaps

Description. Body pale, cylindrical, blunt anteriorly and posteriorly, anterior end slightly everted ( Fig. 12A, B View FIGURE 12 ); 36 mm long, 3 mm wide, cephalic cage 1.5 mm long, 29 chaetigers. Body papillae barely covered with fine sediment particles, forming triangular or tapered tiny lobes. Papillae short, longer than wide, tapered, slightly capitate, sometimes eroded in intersegmental areas, in 16–18 transverse series per segment in anterior chaetigers (chaetiger 10).

Anterior end observed by dissection of one paratype. Cephalic hood short, margin smooth. Prostomium low dark cone, eyes not seen. Caruncle reaching branchial plate margin, dark, lateral ridges darker, median keel pale. Palps thick, contracted, about as long as branchiae; palp lobes low, dark. Lateral lips darker, projected, dorsal and ventral lips reduced.

Branchiae cirriform, sessile on branchial plate, in two lateral groups, about 30 filaments per lateral group ( Fig. 12C View FIGURE 12 ), slightly shorter than palps. Nephridial lobes not seen.

Cephalic cage chaetae as long as 1/24 body length or 1/2 body width. Only chaetiger 1 involved in cephalic cage; chaetae arranged in short lateral series, each with 2–3 chaetae.

Anterior margin of first chaetiger papillated, papillae short, abundant. Anterior chaetigers without especially long papillae. Chaetigers 1–3 becoming slightly longer. Chaetal transition from cephalic cage to body chaetae abrupt; aristate neurospines present from chaetiger 2. Gonopodial lobes in chaetiger 5, dark, cylindrical ( Fig. 12D, E View FIGURE 12 ).

Parapodia well developed, lateral. Median neuropodia ventrolateral. Notopodia and neuropodia close to each other. Notopodia with chaetal lobe short, rounded, with two anterior and two posterior digitate papillae, about 1/3 as long as notochaetae; neuropodia surrounded by small, digitate papillae, most eroded, neuropodial lobes exposed ( Fig. 12F View FIGURE 12 ), with 4–5 inferior elongate papillae.

Median notochaetae arranged in short transverse series, all notochaetae multiarticulate capillaries with short articles basally, medium-sized medially, longer but less defined distally ( Fig. 12G View FIGURE 12 ), 4–5 chaetae per bundle, as long as 1/4 body width. Neurochaetae multiarticulate capillaries in chaetiger 1; posterior chaetigers with aristate neurospines, arranged in short transverse series, 4–5 per bundle; anterior neuropodia with rather straight neurospines ( Fig. 12H View FIGURE 12 ), median and posterior chaetigers with slightly falcate neurospines ( Fig. 12I View FIGURE 12 ).

Posterior end rounded, pygidium with anus terminal, anal cirri absent.

Variation. Paratypes 31–38 mm long, 3–4 mm wide, cephalic cage 1.5–2.0 mm long, 26–29 chaetigers; gonopodial lobes rounded in chaetiger 5.

Remarks. Bradabyssa alaskensis n. sp. resembles B. nuda ( Annenkova-Chlopina, 1922) n. comb. and B. strelzovi (Jirkov & Filippova in Jirkov, 2001) n. comb. by having a long, thick body and first parapodia of a similar size as the following ones. However, they differ in the relative number of chaetigers, even when of a similar size, and especially in the number of neurospines per ramus; B. alaskensis has fewer chaetigers (26–29), notochaetae (1–2), and neurospines per bundle (4–5) than the two other species. Furthermore, B. alaskensis differs from B. strelzovi in the relative size of neuropodia: in B. alaskensis they are barely projecting, whereas they are markedly projecting in B. strelzovi .

Etymology. The species name is derived from Alaska to indicate its type locality.

Distribution. Northern Alaska, Arctic Ocean, from muddy bottoms at about 50 m depth.

GBIF Dataset (for parent article) Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF